Pollution from wildfires and heatwaves is threatening progress toward cleaner air, according to the World Meteorological Organization's 2026 Air Quality and Climate Bulletin.
Released for the International Day of Clean Air for blue skies, the bulletin argues that air pollution and climate change cannot be treated as separate problems. The same extreme heat and dry conditions that raise fire risk can produce smoke that travels far beyond the burning area.
What did the WMO bulletin find?
WMO highlights the growing impact of aerosols and ground-level ozone on health and ecosystems. Aerosols are tiny particles suspended in the atmosphere; some occur naturally, while others come from combustion, industry, transport, agriculture, dust and fire.
One study cited in the bulletin indicates that extreme fire-smoke events have tripled globally since the 1990s. It estimates that such events contributed to nearly 100,000 additional deaths per year between 2010 and 2018, while warning that the true burden may be higher.
That estimate is not a live death count for 2026. It comes from scientific analysis of an earlier period and is included to show the scale of a worsening risk.
Why PM2.5 is dangerous
PM2.5 refers to particles and droplets with diameters of 2.5 micrometres or less. They are small enough to travel deep into the lungs and can enter the bloodstream.
Wildfire smoke contains PM2.5, but fires are not the only source. Industrial activity, residential heating, vehicles, agriculture and dust storms also contribute. This makes exposure a problem for both heavily polluted cities and communities that usually have cleaner air but experience intense smoke episodes.
Air-quality indexes translate pollutant measurements into public guidance. The exact scale and colour categories vary by country, so people should follow their national or local health authority rather than compare numbers from different systems without context.
How climate and air pollution reinforce each other
Hotter, drier conditions can increase the likelihood or intensity of fires in vulnerable regions. Fire smoke then releases particles and gases into the atmosphere, degrading air quality over large distances.
Ground-level ozone can also increase during hot, sunny conditions when precursor pollutants react in the atmosphere. Unlike the protective ozone layer high above Earth, ozone near the surface is harmful to people and vegetation.
Some pollutants also influence the climate. Black carbon absorbs sunlight and can accelerate melting when it settles on snow and ice. This two-way relationship is why WMO calls for coordinated policy rather than isolated air and climate programmes.
Smoke does not respect borders
Fine particles can travel hundreds or thousands of kilometres depending on wind and atmospheric conditions. A city does not need to be close to flames to experience hazy skies or unhealthy readings.
Satellite observations help track smoke plumes, but ground stations remain essential because they measure conditions where people live and breathe. WMO says monitoring remains insufficient for several widespread pollutants, including fine particles, ozone, black carbon and airborne microplastics.
Better observation can improve forecasts and allow schools, hospitals, outdoor workers and people with respiratory conditions to respond earlier.
What should people do during a smoke event?
Public-health advice depends on location and individual risk. In general, official agencies may recommend:
- checking local air-quality alerts;
- reducing strenuous outdoor activity when pollution is high;
- keeping indoor air cleaner by closing windows when appropriate;
- using correctly fitted, effective masks when advised;
- following medical guidance for asthma or heart and lung conditions.
Air cleaners and masks vary in performance. Consumers should rely on recognised health guidance rather than products making unsupported protection claims.
Anyone experiencing severe breathing difficulty, chest pain or other urgent symptoms should seek medical help. This article provides general information, not personalised medical advice.
What governments can do
WMO's central recommendation is coordination. Reducing emissions from transport, energy and industry can improve health while also cutting climate-warming pollution. Better fire management, early-warning systems and smoke forecasting can reduce exposure when fires occur.
International data sharing matters because smoke crosses borders. Consistent observations also help scientists distinguish local pollution from transported smoke and evaluate whether clean-air policies are working.
The bottom line
The 2026 WMO bulletin warns that wildfire smoke and heatwaves can reverse hard-won air-quality improvements. The risk is global, because tiny particles travel across regions and enter deep into the body. Stronger monitoring, clearer warnings and policies that address climate and pollution together are the practical response.
Read more global developments in News and background coverage in World.
